Electromagnetic switch



Sept. 13, 1932 F. MENZEL :Lac'raoueus'nc sun-ca Filed July 28. 192'! v Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE FRIEDRICH MENZEL, OF STUTTGART, GERMANY, ASSIGNOR TO ROBERT BOSCH AKTIEN- GESELLSCHAFT, OF STUTTGART, GERMANY ELECTROMAGNETIC SWITCH Application filed July 28, 1927, Serial No. 209,001, and in Germany January 20, 1927.

This invention relates to improvements in electromagnetic switches particularly adapted for use with vehicle lighting sets but also capable of other uses and of the type in which the armature actuates a plurality of contacts in succession.

Hitherto in such constructions one or both contacts of the first pair have been resiliently mounted for this purpose so that they provide a spring resistance to the electro-magnetic armature during and after closing. Thus the pressure caused by the armature after closing the first pair of contacts has to be relatively high as otherwise the contacts 5 could open at the wrong time as a result of external vibrations or shocks.

In order to render this unnecessary, the armature may, according to the invention, be moved further after closing the one pair of contacts unretarded by the latter in the given direction. Further by this construction a relatively large armature movement can be controlled by means of a relatively small electro-magnet since the initially small attraction of the magnet is increased by the :prting provided to close the first pair of conac s.

One formof construction of the invention is shown in the drawing which is a section through a combined control switch for a vehicle lighting set together with a diagram ofconnections.

An iron core 2 having two coils 3 and 4 is mounted on the base plate of an iron frame 1 and the armature 5 is suspended from the frame 1 by means of a leaf spring 6. The armature 5 is provided with a rectangular bent arm 7 with abutment 8. An insulating plate 9 connected with the frame 1 carries two fixed contacts 10 and 11 and a leaf spring 12 on which rests a contact 13 which, in the position of rest of the spring 12, is forced by it against the contact 11, and a stop 14, which faces the abutment 8 through a hole in the insulating plate 9 and the frame 1. There is also mounted on the frame 1 an angle iron 15 having a contact 16 and a Z-shaped spring 17 with contact 18.

10 is the fixed contact and 18 the movable contact, according to the invention, of the switch for connecting the apparatus with the battery. 11 and 16 are the stationary contacts and 13 the movable contact of the dynamo regulator. I

One end of each of the coils 3 and 4c is connected with the plus brush of the armature 19 of the dynamo. The other end of the coil 3 is connected to the contact spring 17 whilst the second end of the coil 4 is earthed. A lead is taken from the fixed switch contact 10 to the plus pole of the battery20. The excitation winding 21 of the dynamo is connected in series with a resistance 22 between the plus pole of the dynamo and earth. spring 12 is connected with a lead which is taken from the point of connection of the excitation winding 21 and the resistance 22. The regulating contact 16 is connected with the plus brush of the dynamo and the contact 11 to earth.

In the position of rest of the regulating switch shown, the armature 5 is held away from the iron core 2 by the leaf spring 6 so that the switch spring 17 is bent to the right of the end of the arm 7. The switch contacts 10 and 18 are consequently open and no back current can fiow from the battery 20 to the lighting dynamo 19, 21. The abutment 8 of the arm 7 is separated from the stop 14 of the spring 12 and therefore the contacts 11, 13 of the regulator are closed whereby one end of the excitation winding 21 is earthed through the spring 12 and contacts 11, 13 and the resistance 22 is short circuited.

As soon as a potential is set up by the lighting dynamo 19, 21'the coil 4 is excited and the armature 5 is attracted by the iron core 2 whereby the armature arm 7 moves towards the stop 14. The contact spring 17 follows this movement until its contact 18 strikes against the fixed contact 10 whereby the switch isv closed and the lighting dynamo is connected with the battery 20 through the current coil 3, spring 17 and the contacts 18 and 10.

On the voltage produced by the lighting dynamo increasing the armature 5 is attracted still further to the iron core 2 leaving the spring 17, and finally its abutment 8 strikes the abutment 14. The leaf spring 12 is thereby moved so that first the contacts 11 and 13 are separated whereby the resistance 22 is switched into the circuit of the excitation current and then the contacts 13 and 1(i are closed, whereby the excitation windmg 21 is short-cricuited through the spring 12 the contacts 13 and 16, the angle iron 15, frame 1 and the relatively low resistance current-winding 3. The regulator thus works in the manner of the known vibration regulator.

If the velocity of revolution of the lighting dynamo decreases considerably the armature will be withdrawn from the iron core 2 by the spring 6. In this movement the armature arm 7 finally strikes against the contact spring 17 and bends it back so that the switch contacts 10, 18 are separated and the lighting dynamo is cut off from the battery 20.

As in its return to the position of rest the armature arm 7 has to separate the switch contacts 10 and 18 against the force of the spring 17 the previous opening of the switch contacts as a result of shocks or vibrations during travel, is prevented. The mounting of all the contacts independently of the armature allows of a simple construction and of the combination of the insulated contacts on a single insulating plate to give an easy construction of the whole apparatus. Further, all the elements regulated by the armature can easily be arranged so that their path is tangential to the portion of the are through which the armature passes at any moment; thus scraping movements between the armature and the elements controlled thereby, the friction of which could prevent the movement of the switch, are prevented.

The excitation of the lighting dynamo can also be actuated by the regulator in a different manner from that described for example by putting further excitation windings in and out of circuit. In that case it is only necessary to connect the excitation contacts 11, 13, 16 suitably to the connecting net-work concerned. The regulator may also be constructed as a carbon regulator instead of as a contact regulator the contacts of which only press on one another with alternating pressure but are not however, separated from one another.

Instead of being combined with a regulator the switch may also be combined with any other device, for example one which is connected to an optical or acoustic signalling apparatus. The signals are then actuated by opening and closing the emitacts 11, 13, 16.

The leads connected to the windings of the electro-magnet and to the contacts actuated by the armature can serve suitable' purposes. The construction of the electromagnets can also be varied as desired w1thout departing from the scope of the invention. Thus for example the number of contact springs 17 assisting in the closing of the armature can be increased and correspondingly also the number of the pairs of contacts 10, 18 which do not prevent the closing movement of the armature.

\Vhat I claim is.:

1. In an automatic cut-out and regulator for battery charging systems, a cut-out switch, a vibratory regulator switch, tension means tending to close the cut-out switch, a common actuating magnet and armature for both said switches, said armature being normally in engagement with the cut-out switch to hold the same open and arranged upon actuation first to move out of operative engagment with the cut-out switch permitting the same to close and upon further movement to come into cooperative engagement with the regulator switch only.

2. In an automatic cut-out and regulator device for battery charging systems, an actuating magnet, an armature for the magnet, tension means for biasing the armature in a given normal position, a cut-out switch normally held open by the armature and its tension means, and tension means tending to close the cut-out switch, a vibratory regulator switch arranged for operation by said armature, said armature being arranged to move out of engagement with said cut-out switch, after permitting the same to close, and move into operative engagement with the regulator switch.

An automatic cut-out and regulator switch for battery charging systems, comprising a pair of switch contacts, an electromagnet and armature therefor arranged upon deenergization of the magnet to hold said switch contacts open and upon energization to move out of operative connection with said switch contacts, and a Vibratory regulator contact mounted separately from said switch contacts and arranged to be operated by said armature while said armature is out of operative connection with said switch contacts.

4. In an automatic cut-out and regulator switch for battery charging systems, a n a etuating magnet, an armature for said magnet having a given extent of movement, a pair of switch contacts mounted independently of the armature, a pair of regulator contacts including a vibratory contact mounted independently of the armature and normally out of operative engagement therewith and means for operatively connecting the armature to the different sets of contacts one to the exclusion of the other during different portions of its given extent of movement respectively.

5. In an automatic cut-out and regulator device for battery charging systems, a cutout switch and a vibratory regulator switch, actuating members for said switches, an actuating magnet and armature therefor, said armature being arranged to move between said switch actuating members to engage and Operate the same one at a time, and tension means tending to close the cut-out switch and assist in the movement of the armature toward the magnet only during operation of the cut-out switch.

6. An automatic switch as claimed in claim 3 in which one of each of said pairs of contacts in mounted on a common insulating plate.

7. A switch as claimed in claim 1 in which the switch operating portion of the armature moves in an arc, and the portion of the switch engaged by the armature is constrained to move in a path approximately tangent to the portion of the are passed over by said switch operating portion of the armature during engagement of the armature with the switch.

8. A switch comprising an electrically controlled armature, a movable spring contact tending to move said armature, a stationary contact cooperating with said spring contact and arranged to limit the extent of movement of said spring contact and prevent it from further following the armature, and a vibratory contact arranged to be closed by further movement of said armature beyond the point where movement of the armature is assisted by said s ring contact.

In testimony w lereof I have hereunto afiixed my signature.

FRIEDRICH LENZEL. 

